Compared with an ordinary light source, LED lamps have characteristics of high efficiency, environmental protection and long service life, so they are becoming a mainly selective solution for reducing energy consumption of indoor and exterior lighting.
As the LED lighting system market is growing continually, in addition to a need for high power conversion efficiency during normal operation, standby power consumption also becomes a focus that is commonly paid attention to in the LED industry. Many countries and districts in the world have all constituted corresponding regulatory standards to raise a threshold for admitting LED lamps, for example, Europe has stipulated that power consumption of LED in a standby mode shall be lower than 0.5 W.
In a conventional LED lighting application, there are usually two ways for an LED driver and an LED lamp to become standby: the first one is to switch off the power supply line by an external power relay, the second one is to switch it off using a digital interface such as a digital addressable lighting interface (DALI). Switching off the power supply line by the external power relay may reduce the standby power, but the price is relatively expensive and personnel is needed to manually switch off, which cannot achieve remote controllability nor can take advantage of flexible control of the building LED lighting system. In a conventional DALI and other addressable driving systems, instructions for shutting down require the circuit to have a low voltage for keeping active, therefore, the energy consumption in a standby state is still around 10% of that in normal operation, still greater than 0.5 W.
Therefore, it is necessary to provide a simple circuit for shutting down the driver without switching off the power supply line, to solve the technical problems as mentioned above.